Method and apparatus for winding up metal strips onto a winding mandrel

ABSTRACT

The invention relates to a method and an apparatus for winding up metal strips ( 2 ) onto a winding mandrel ( 3 ), which is arranged in a reeling shaft ( 1 ) and to which the metal strip is passed by a driver having a lower and an upper driver roller ( 5, 6 ), wherein a table ( 7 ) is provided underneath the metal strip ( 2 ) for guidance and a pivotable strip diverter and, adjoining the latter almost up to the winding mandrel ( 3 ), a pivotable shaft flap ( 11 ) are arranged above the metal strip. By measuring the strip tension in the reeling shaft, it is intended to regulate the driver in such a way that the running of the strip makes it possible for the metal strip to be wound up to form a coil with straight edges. To achieve this, the longitudinal tensile force exerted on the metal strip ( 2 ) by the driver is determined by means of a strip tension measuring device ( 13 ), which dips into the metal strip from above in the reeling shaft ( 1 ), and the measuring signal is passed to a driver regulating device ( 22 ) to control the running of the strip by the driver. In the case of an apparatus suitable for this purpose, the strip diverter is formed as a strip tension measuring device ( 13 ) which dips into the metal strip ( 2 ) from above and is provided with a diverter body, which has a rotatably mounted roller arm ( 16 ), carrying a roller ( 17 ) at its front end, wherein a force measuring means ( 20 ) that is connected in signalling terms to the regulating device ( 22 ) is arranged between the diverter body and the roller arm ( 16 ).

The invention relates to a method of and an apparatus for winding metal strips on a mandrel in a coiler to which the metal strip is supplied by a feeder comprising a lower and an upper feed roller, a guide plate being provided under the metal strip for guidance and a pivotal strip diverter and a pivotal upper guide plate following this diverter almost up to the mandrel being provided above the metal strip.

A feeder known from DE 195 20 709 [U.S. Pat. No. 5,961,022] comprises a fixed-axis lower roller and an upper roller that can be moved relative to it. The adjustable upper roller is supported in a pivot frame that can be adjusted by hydraulic or pneumatic cylinders and that is formed by two spaced rocker arms connected at a common pivot axis by a base supported on both sides in the feeder frame. This upper roller can be pivoted by individually actuatable fluid-powered cylinders, the base connecting the rocker arms being formed by a torsion spring.

Different pivot angles of the rocker arms and therewith of the adjustable upper roller can be achieved here by introducing different adjustment forces at a relatively low different force of the fluid-powered cylinders because the tension exerted by the feeder on the strip can be influenced by pivoting the upper roller and tension can be distributed in this manner.

DE 197 04 447 [U.S. Pat. No. 6,070,472] teaches a measuring roller for measuring the evenness of a roll strip under tension in a hot-strip roll train. One or more of these measuring rollers is pressed from below against the roll strip and positioned between the roll frames of the finishing train and/or in the roll direction downstream of the last roll frame of the finishing train and/or upstream of a drive apparatus for a reel and/or between the drive apparatus and the reel. In a measuring roller between the drive apparatus and the reel the measured value obtained can be used to pivot the drive apparatus and the strip travel can be controlled during winding onto the reel mandrel in this manner.

DE 199 53 524 [U.S. Pat. No. 6,470,722] describes a looper that can measure the radial variation in thickness present on account of the longitudinal tension prevailing in a metal strip over the strip width. The looper comprises to this end a looper roll supported at each end on a respective pivot arm. The pivot arms are subdivided at a hinge into a shaft arm part and a roller arm part and are connected to a looper shaft. The hinge transmits a return force exerted by the metal strip on the looper roller adjusted from below against the metal strip onto force sensors on the pivot arms. The return force corresponds to the longitudinal tension so that it can be determined from the measured return forces. In order to prevent the roller arm part from lifting off the force sensor, the shaft arm and the roller arm are connected to one another by a retaining element. The upstream and downstream travel directions that are determined for example by the roll frames or feeders, can be readjusted, as well as the speed or the roller positions can be adjusted either on the basis of the total longitudinal tension or of the determined vectors.

The basic object of the invention is to develop a method and an apparatus of the above-described type in such a manner that an improved measuring of the tension of the metal strip in the coiler can be achieved for controlling the driving apparatus or feeder to so influence strip travel that a square-end coil can be formed.

This object is attained in accordance with the invention with a method in that a strip-tension measurer engages downward into the coiler from above with the metal strip, determines the longitudinal tension exerted by the feeder on the metal strip, and feeds an output corresponding thereto to a feeder controller. As a result of the engagement of the strip-tension measurer from above with the metal strip, in particular an optimal contact angle can be maintained even on the strip end. This would not be possible if the strip-tension measurer were engaged from below, since in this case the contact angle is severely limited by the strip guide including the guide plate required above the metal strip and becomes so small that no reliable measurement is possible on the strip end. However, the measuring on the strip end is important because strip guidance is particularly difficult here on account of there being no tension exerted on the strip by the finishing frame of the rolling train.

The invention proposes that the variation in thickness caused by the longitudinal tension in the metal strip over the strip width and determined by the strip tension measuring apparatus engaging downward at a contact angle with the metal strip is determined by how much the measured support forces deflect the suspension support of the strip-tension measurer.

To this end, according to a preferred embodiment of the invention, for the direct or indirect measurement of support force the contact angle between the strip-tension measurer engaging downward with the metal strip is used. The contact angle transfers force from the metal strip to the roller and from the latter to the force sensor integrated in the strip-tension measurer.

In order to actuate the strip-tension measurer at least one cylinder is required, according to the invention a controlled-stroke pivot cylinder braced against a downstream pivot arm. Alternatively, there can be two pivot cylinders. Another possibility for actuating the strip-tension measurer is to provide the strip-tension measurer in a U-shaped frame engaged by a cylinder at a symmetry axis of the frame.

It is recommended here that the contact angle be held approximately constant by controlling the amount of engagement of the roller. The contact angle is a function of the stroke of the pivot cylinder or cylinders and the diameter of the wound coil. In order to maintain an optimal winding during the entire winding method the stroke of the at least one pivot cylinder can be monitored. The theoretical value can be calculated during the winding method independently of the instantaneous coil diameter, the optimal winding and the position data. In order to detect the stroke, a path sensor can be built into the pivot cylinder in or on the cylinder; optionally, the strip-tension measurer, which can be pivoted in, can be provided with an angle sensor, so that the stroke of the pivot cylinder can be calculated. The instantaneous diameter of the coil can be calculated by a rotation counter of the mandrel and a strip-thickness sensor. Alternatively, the coil diameter can also be directly measured, e.g. by an optical laser sensor.

According to a further advantageous embodiment of the invention the roller of the strip-tension measurer is rotated up to the speed of the metal strip prior to engagement therewith. Since the roller is pivoted during the winding method into the strip, this speed synchronization can avoid damage to the metal strip by a subsequent acceleration that otherwise might occur. The roller drive can take place mechanically and/or electrically and/or hydraulically.

An apparatus for solving the problem constituting the object of the invention, in particular for carrying out the method, is characterized according to the invention in that the strip guide is designed as a strip-tension measurer that can be pivoted from above into the metal strip and that is provided with a guide body that comprises a rotatably supported roller arm that carries a roller on its front end, and that a force sensor is provided between the guide body and the roller arm, which sensor is connected by output technology to a controller of the feeder. The strip-tension measurer in accordance with the invention thus fulfills the classic strip guide function at the same time. Namely, the entire strip-tension measurer pivots counterclockwise from the out-of-operation position, that is, the raised out-of-use position, downward into the operating position, engaging downward with the metal strip that is running in and guides the metal strip to the following mandrel with an activated measuring at the same time.

The function of the strip-tension measurer as simultaneous strip guide is preferably supported by the fact that at least one front section of the guide plate following the lower roller of the feeder under the metal strip is designed as a pivotal flap. This flap can pivot counterclockwise about the axis of the lower feed roller.

According to an advantageous embodiment of the invention the guide body connects a rear pivot arm to a front pivot arm of the strip-tension measurer. In the case of only one pivot cylinder that would be attached in the rear and thus on the drive side, the guide body receives, as connection between the pivot arm on the drive side to the pivot arm on the operator side, the torsion load that would be produced by a one-sided actuation of the strip-tension measurer by only one rear- or drive-side pivot cylinder.

If a driven guide roller is advantageously arranged in the axis of rotation of the strip-tension measurer that is at a spacing from the roller arm receiving the driven roller, the metal strip can be protected from damage when it is guided on the path from the lower feed roller to the next roller of the following coiler.

A variant of the invention provides that the strip-tension measurer is arranged with the roller arm facing the mandrel integrated into the upper guide plate. A combination of strip-tension measurer and upper guide plate is present in this arrangement. The front roller of the strip-tension measurer would follow a upper guide plate extending up to the first pressure roller of the mandrel and the free space toward the upper roller of the feeder would be filled out with a conventional guide.

Further features and details of the invention result from the claims and the following description of an illustrated embodiment of the invention presented in the drawings.

FIG. 1 shows a schematic side view of a prior-art coiler;

FIG. 2 shows a schematic side view of a coiler with a strip-tension measurer that can pivot from above into the metal strip, simultaneously acts as a strip guide, and when not in use is lifted off the metal strip;

FIG. 3 shows the subject matter of FIG. 2 with the strip-tension measurer pivoted into the measuring and use position shortly before the end of a winding operation; and

FIG. 4 is a cross section through a detail of a guide roller mounted in the strip-tension measurer.

A prior-art coiler 1 as shown in FIG. 1 is downstream of the rolling train or finishing frame and winds up the rolled metal strip 2 on a mandrel 3 to a package or coil 4 (see FIG. 3). The metal strip 2 is supplied to the mandrel 3 by a drive apparatus or feeder of which only the upper and lower feed rollers 5 and 6 are shown here. A lower guide plate 7 travels from the lower feed roller 6 to the mandrel 3. The leading end of the metal strip 2 fed in this manner first engages a first pinch roller 8 associated with the mandrel 3 and is followed by more such rollers distributed over the mandrel's circumference.

A strip guide 9 that contacts the upper feed roller 5 in the out-of-use position for receiving the strip is located above the metal strip 2. The strip guide 9 is pivoted by a cylinder 10 that has a piston rod connected to a pivot arm of strip guide 9. The coiler 1 is closed at the top by a upper guide plate 11 traveling from strip guide 9 to the mandrel 3. A cylinder 12 is articulated to upper guide plate 11 for pivoting it.

In the embodiment of the coiler 1 shown in FIGS. 2 and 3 parts the same as those of the above-described coiler are identified by the same reference numbers. A significant difference here is a strip-tension measurer 13 that also acts as the strip guide. It consists of rear drive-side and front pivot arms 14 of which only the rear drive-side pivot arm can be seen in FIG. 2. The two pivot arms 14 are connected to one another by a torque-transmitting guide body 15 (see FIG. 4). Moreover, it comprises a roller arm 16 at whose outer end a driven roller 17 is rotatably supported. The roller arm 16 is can oscillate about a pivot 18. In order to not swing down because of gravity, the roller arm 16 is held in position by a retaining element 19.

As soon as the strip-tension measurer 13 pivots from above down against the metal strip 2 and engages down into it with its roller 17 while forming a contact angle, a force is applied to the roller 17 that is applied to the roller arm 16 in a clockwise direction. However, clockwise rotation of the roller arm is prevented by a force sensor 20 that also braces the roller arm 16, determines a force produced at the axis 21 of the support, and transmits it as a measurement output to a controller 22 (see FIG. 3). The latter can be controlled in such a manner dependent on the measurement, e.g., by pivoting the upper and/or lower feed roller(s) 5 and 6 or by a parallel pivoting of both rollers or by applying different forces on the drive side and operator side so that a straight-edged coil 4 can be produced on the mandrel 3.

The strip-tension measurer 13 is provided on its downstream (in the direction of the strip travel) end at a spacing from the roller 17 with a guide roller 23 provided in its axis of rotation, as shown in FIGS. 2 and 3 as cross section in the area of pivot arm 7 through the pin of guide roller 23. Here too the coiler 1 is closed at the top by an upper guide plate 11 that can be pivoted by a cylinder 12. The guide plate 7 that extends underneath the metal strip 2 from the lower feed roller 6 to the mandrel 3 and conducts the metal strip 2 is provided at least on its upstream end with a flap 24 that can pivot counterclockwise about the axis of lower feed roller 6.

FIG. 3, which shows the shortly before the end of an operation winding the metal strip 2 to a finished coil 4, can be accurately determined on the one hand from the contact angle that the metal strip 2 forms where it engages the roller 17 of the strip-tension measurer 13. On the other hand, different measurement outputs 25 and control outputs 26 are indicated by dotted lines that are fed to the controller 22 or are outputted from it to pivot actuators of the upper and lower feed rollers 5 and 6 (see dotted lines 26). The parameters essential for determining and, if necessary, maintaining constant an optimal contact angle during the entire winding method are set, for example, by determining the stroke of the pivot cylinder or cylinders 10 of the strip-tension measurer 13, which cylinder(s) is/are provided by a movement sensor, by an angular-position sensor of the strip-tension measurer 13, or from the instantaneous diameter of coil 4. This diameter can be determined by sensors counting revolutions of the mandrel 3 (see dotted line 25 starting from it) and detecting the strip thickness. Direct measuring of the diameter of coil 4 is possible, as by the illustrated optical laser sensor 27.

In any case, it is possible to make a measurement output available from the strip tension measurer in the coiler for a feeder controller. This can take place alternatively to the embodiment shown in the combination the strip-tension measurer with the strip guide and also by a combination of the strip-tension measurer with the upper guide plate. The strip-tension measurer 13 shown in FIGS. 2 and 3 would then be integrated in the upper guide plate 11 with its roller 17 facing the mandrel 3, i.e. symmetrically to both sides of line A-A in FIG. 2. The space that is then free from upper feed roller 5 to the strip-tension measurer 13 could be filled out or bridged over in this option by a conventional strip guide 9 (see FIG. 1).

List of reference numerals 1 coiler 2 metal strip 3 mandrel 4 package/coil 5 upper feed roller 6 lower feed roller 7 guide plate (guide plate) 8 pressure roller 9 strip guide 10 cylinder 11 upper guide plate 12 cylinder 13 the strip-tension measurer 14 pivot arm 15 guide body 16 roller arm 17 roller 18 pivot 19 retaining element 20 force sensor 21 force axis 22 feeder-controller 23 guide roller 24 pivotal flap 25 measurement output 26 measurement output 27 optical laser sensor 

1. A method of winding metal strips on a mandrel of a coiler to which the metal strips are conveyed by a feeder having a lower and an upper feed roller, a guide plate being provided under the metal strip, a pivotal strip guide and a pivotal upper guide plate downstream of the pivotal strip guide extending above the metal strip almost to the mandrel, wherein a strip-tension measurer engages downward into the coiler from above with the metal strip and determines the longitudinal tension exerted by the feeder on the metal strip and feeds an output corresponding thereto to a feeder controller.
 2. The method according to claim 1 wherein the variation in thickness of the distribution of tension is determined by how much the measured support forces affect the suspension of the strip-tension measurer.
 3. The method according to claim 1 wherein a contact angle of a roller engaged downward with the metal strip during the pivoting in of the strip-tension measurer is used for the direct or indirect measuring of the support force.
 4. The method according to claim 3 wherein the contact angle is held approximately constant for controlling extent of engagement of the roller.
 5. The method according to claim 3 wherein the roller is previously rotated up to the speed of the metal strip before pivoting in.
 6. An apparatus for winding metal strips on a mandrel arranged in a coiler to which the metal strip is supplied by a feeder comprising a lower and an upper feed roller, in which a guide plate is provided under the metal strip for guidance and a pivotal strip guide and a pivotal upper guide plate extend downstream from this guide almost up to the mandrel above the metal strip wherein the strip guide is designed as a strip-tension measurer that can be pivoted from above down into engagement with the metal strip and that is provided with a guide body that has a pivotal roller arm that carries a roller on its outer end, and that a force sensor is arranged between the guide body and the roller arm and sends an output to a controller of the feeder.
 7. The apparatus according to claim 6 wherein the guide body connects a back pivot arm to a front pivot arm of the strip-tension measurer.
 8. The apparatus according to claim 7, further comprising at least one controlled-stroke pivot cylinder engaging the back pivot arm.
 9. The apparatus according to claim 6 wherein the roller supported in the roller arm can be driven.
 10. The apparatus according to claim 6 wherein a driven guide roller is arranged at the axis of rotation of the strip-tension measurer, which axis is at a spacing from the roller arm.
 11. The apparatus according to claim 6 wherein at least a front part of the guide plate downstream of the lower feed roller and under the metal strip is a pivotal flap.
 12. The apparatus according to claim 6 wherein the strip-tension measurer is integrated into the upper guide plate with the roller arm and extending toward the mandrel. 